Semi-automatic transmissions are being provided on many vehicles. With a semi-automatic transmission, the driver of the vehicle has control of the transmission by using a shifter with the advantage that the driver does not have to actuate a separate clutch actuator. When the driver actuates the shifter, a signal is sent to a control unit of the transmission which sends signals to cause a clutch connected to the transmission to disengage, to cause the transmission to shift gear once the clutch is disengaged, and to engage the clutch once the transmission has shifted gear. In another type of semi-automatic transmission, when the driver actuates the shifter, a signal is sent to a control unit of the transmission and engine which sends signals to cause the ignition to be cut, thus momentarily reducing engine torque, to cause the transmission to shift gear while ignition is cut, and to resume ignition once the transmission has shifted gear. By electronically controlling these operations, the transmission will consistently be shifted smoothly which sometimes not the case when an inexperienced driver has to actuate both a shifter and a clutch actuator in a vehicle equipped with a manual transmission. This also greatly reduces the likelihood of the vehicle stalling because of a failed shifting attempt which is common when vehicles equipped with manual transmissions are driven by inexperienced drivers.
On vehicles equipped with a semi-automatic transmission, the shifter usually only controls the selection of forward gears of the transmission (i.e. gears which when selected cause the vehicle to go forward). On vehicles which have a fully automatic transmission mode and a semi-automatic transmission mode, when in the semi-automatic mode, the shifter only control the selection of forward gears of the transmission and the reverse gear can only be selected when in the fully automatic mode.
Some vehicles have a transmission with forward gears and use a separated reverse system to allow the vehicle to move in a reverse direction. One example of such a reverse system is described in U.S. Pat. No. 6,267,192 (the '192 patent), issued Jul. 31, 2001, the entirety of which is incorporated herein by reference. In the reverse system described in the '192 patent, the starter motor is used to drive the vehicle in reverse. Although this system allows the vehicle to move in the reverse direction, the added reversing system increases the complexity of the vehicle.
As would be understood, it would be desirable to have a semi-automatic transmission where the shifter can be used to select a reverse gear of the transmission. However, the control of semi-automatic transmission needs to be provided with certain features in order to prevent causing the semi-automatic transmission to select a reverse gear when doing so may damage the semi-automatic transmission or other components of the engine.
Therefore, there is a need for a vehicle having a semi-automatic transmission with a reverse gear.
There is also a need for a method of controlling a semi-automatic transmission with a reverse gear.